Marine speedometer



Filed Jan. 4, 1965 FIGA Y2" 44 H63l FIG. 2 F'IG.4

INVENTOR. FRANKLIN P. LEPIRD ATTORNEY BY #MM MM United States Patent 3,327,530 MAPJNE SPEEDMETER Franklin P. Lepird, '73 Liberty St., Quincy, Mich. 49682 Fiied dan. 4, i965, Ser. No. 422,921 '7 Ciaims. (Cl. '7S-182) ABSTRACT F THE DISCLSURE A purging device for a marine speedometer of the Pitot tube type. A hand .pump closes the channel from the Pitot tube inlet to the indicating mechanism and forces air in a reverse direction through the Pitot tube opening.

This invention relates generally to marine speedometers `of the pressure sensitive type including a Pitot tube and more particularly to means for directing a reverse flow of pressure iluid to the Pitot tube for cleanout purposes.

Pressure sensitive speedometers including a Pitot tube are well known in the art and have found widespread use in the marine field to indicate the speed at which a boat hull is :being propelled through the water. However, an inherent shortcoming in such a device is that the Pitot tube opening of necessity must be immersed in and propelled through the water and in such a position is subject to being brought into contact with dirt, weeds and other foreign material often found therein; which foreign material easily enters and accumulates within the opening and the conduit means connecting the same to the pressure sensing portion of the speedometer. This foreign material then blocks the conduction of pressure signals and interferes with or even disables the operation of the speedometer.

The prior art devices require that the operator either mechanically cleans out the accumulated foreign material or some devices, for example that shown in United States Patent 2,362,298, provide an arrangement wherein the operator may apply a back pressure to the conducting means and Pitot opening to blowout foreign material.

However, in devices Iof the type disclosed in the above mentioned patent, numerous valve must be manipulated by the operator to introduce the back pressure while insuring that the same is not directed to and damages the pressure sensing portion of the speedometer and, after completion of the blow-out operation, such valves must again be manipulated to return the system to an operative arrangement.

It is, therefore, an object of this invention to provide a marine speedometer device having a Pitot tube and means connecting the same to the pressure sensing portion of the speedometer which device includes means for automatically directing a blow-out back pressure to the conducting means and Pitot opening.

It is another object of this invention to provide such a device wherein the automatic means also insures that the blow-out back pressure is not directed to the pressure sensing portion of the speedometer and that upon completion of the blow-out operation the system is returned to its operative condition.

Further and other objects of this invention will become apparent upon a reading of the specification when taken in view of the drawings wherein:

FIG. l is a schematic View, partially in section, of a speedometer assembly incorporating this invention;

FIG. 2 is a longitudinal sectional view of a portion of the automatic valve of the speedometer assembly;

FIG. 3 is an end View of the valve portion shown in FIG. 2;

FIG. 4 is a view from the opposite end iof the valve portion from that shown in FIG. 3; and

FIG. 5 is a view of the valve of the speedometer as- 3,327,53@ Patented .lume 27, i967 sembly in an operative position yother than shown in FIG. l.

As an example of one form in which this invention may be embodied and lreferring to the drawings, the speedometer system of the present invention is shown generally at l0 and includes a strut l2 adapted to project below the surface of the water, conducting means i4 which extends from the strut and pneumatically connects the same to an indicator 16 wherein variations in pneumatic pressure are accurately translated to a visual indication of the speed at which the strut and the boat hull, shown fragmentarily Vat 17 and to which the strut is attached, are moving relative to the water.

More particularly, the strut 12 is of a vertically elongated nature and is adapted to be suitably attached to the boat hull 17 as by a bracket 18 formed integrally with and secured to the strut `and bolted to the hull. The actual shape and size of the strut 14 and the means attaching the same to the boat hull may take any of a number of forms well known in the art; however, it should be noted that a Pitot opening 20, which is formed in the lower end of the strut, is positioned parallel to the fore and .raft axis of the boat hull 17 and is located below the level of the hull and points directly forward so that, in a well known manner, the same will be immersed in the water supporting the hull and water pressure signals generated by relative movement of the strut and the water will be picked-up by the Pitot opening and transmitted by the conducting means i4 to the indicator 16.

The top of the strut l2 is provided with a reduced portion 22 to which is suitably secured, as by a clamp 2d, a conducting tube portion 26 of the conducting means ld. The Pitot opening 2t) is substantially L-shaped and is open at the reduced portion 22 and coniiuent with the tube 26. The tube portion 26 is made to a suitable length so that the strut l2 may be properly positioned relative to the boat hull i7 and indicator i6. A second conducting tube portion 28 of the conducting means 14 is suitably secured to a pneumatic inlet 30 on the indicator 16 as by a clamp 32, and a blow-out means 34 is interposed between the conducting tube portions 26 and 28 to complete the conducting means i4.

More particularly, the blow-out means 34 includes a valve 36 and a source of pressurized uid 38. The valve 36 is of generally cross-shaped configuration and includes opposed nipples 40 and 42; the nipple 40 being received in the conducting tube portion 26 and having the latter secured thereto as by a clamp 44 and the nipple 42 being received in the conducting tube portion 28 and having the latter secured thereto as by a clamp 46. The nipples di) and 42 define aligned 'bores 41S and 50 respectively which bores are separated by a valve stem bore 52 `disposed normally thereto; the latter bore 52 being disposed in the aligned nipples 5d and 56.

A valve stem 58 is slidably disposed in the bore 52 and, as seen in FIG. l, is normally biased to the left into abutting engagement with a snap ring 6G by a spring 62; the snap ring being suitably secured in a groove in the left end of the bore 52. The spring 62 engages the right end of the stem 58 and is compressed between the latter and the inner surface of a plug 64 threadedly received in the right end of the nipple 56. A passage 66 is formed transversely in the stern 58 and positioned so that when the stem is in its leftward position as shown in FIG. 1, the passage is confiuent with the bores 4S and 59 and pressure signals entering the Pitot opening 2i) will -be transmitted therefrom through the conducting tube 26, the

valve 36 and the conducting tube 2@ to the indicator 16.

The valve stem 58 is provided with a blow-out passage 68 which is formed as a slot that commences from the left end 59 of the stem and extends axially to the right. A substantial portion of the left end 59 of the stem 5S is unaltered by the passage 63 so that, upon the application of fluid pressure to the left end, at a pressure sufficiently high to induce a biasing effect to the stern S8 greater than the spring 62, the stem 58 will be moved to they right, as seen in FIG. 5, so that the right end of passage 68 becomes confluent with the bore 4S.

it should be noted that the stem 5S is preferably dimensioned so that as the same moves to the right, the passage 66 will be completely Within the nipple 56 before the blow-out passage 68 moves into a confluent relationship with the bore 48; the land area 76 on the stem 58 between the passages 66 and 63 being of a sufficient axial extent to block the bores 48 and Si) during the interim period as the stem moves to the right. This insures that passages 66 and 63 cannot become confluent and any blow-out fluid pressure in passage 68 cannot be inadvertently directed through the passage 66 to the bore Sil, but may only flow from the passage 68 to the bore d8. The nipple 56 is of sullicient length so that the portion of the stem to the right of the passage 63 may move thereinto while the left end of the plug 64 serves as a stop for limiting rightward movement of the stem and a counterbore 65 in the left end of the plug 64 completely receives the compressed spring 62.

Means are provided to inhibit rotation of the stem 5S. More particularly, the plug 64, within the counterbore 65 therein, is provided with a slot 72 which receives a tang 74 formed on the right end of the spring 62, while the right end of the stern 58 is provided with a slot '76 which receives a tang 78 formed on the left end of the spring 62 so that upon movement of the stem between its left and right positions the spring 62 prevents the stem from rotating about its elongated axis.

The source of pressurized fluid 33 is a manually operated pump having an elongated cylinder Si) which is reduced in size at its right end 81 and secured in a confluent relationship to the left end of the nipple 54 by a coupling 82. The cylinder Sli is shown received in an opening 84 formed in a suitable portion of the boat hull 417, and along with the indicator 16 which is received in an opening 86 in the boat hull, is preferably disposed in a convenient location which is easily accessible to the operator of the boat; however, the cylinder and indicator may be located at locations remote from each other and the length of the conducting tube portion 2S may be varied to accommodate such remote positioning. For convenience, the cylinder and indicator can be formed in an integral housing. Flanges 88 and 90 are formed adjacent the left ends of the cylinder Sil and the indicator 16 respectively so that the same may be secured to the hull 17 as by screws 92.

Slidably disposed in the bore 94 of the cylinder 86 is a piston 96 having a piston rod 98 extending leftwardly therefrom through an opening 160 formed in a wall 102 threadedly received in and enclosing the left end of the cylinder. A spring 104 is positioned between the wall 102 and the piston 96 and biases the piston to the position shown in FG. l, in which position the piston 96 is displaced slightly to the left of an annular shoulder 106 formed at the junction of the cylinder 80 and its reduced portion S1. An opening 108 is provided in the piston 96 and a first pump valve 110 is positioned to close the right end of the opening. The valve 110 is carried by a relatively weak leaf spring 112 which is secured to the right side of the piston 96 by a screw 114, which leaf spring normally biases the Valve into a closed relationship with the opening 108. A second pump valve 116 is positioned to the right of the shoulder 166 and is biased to almost close the opening 167 therein by a leaf spring 118 secured thereto and secured to the shoulder 106 by a screw 120.

To actuate the pump 3%, the operator grasps a handle 122 threaded onto the left end of the piston rod 98 and pulls the same and the piston 96 to the left. The valve 110 is biased open .by the compressing of the fluid to the left of the piston 96 which fluid enters through the space in the opening around the piston rod 93 and then flows through the opening 103 and occupies the space tothe right of the piston. The handle 122 is then forced to the right which carries the piston 96 to the right against the shoulder 166 and compresses the fluid to the right of the piston 96, the valve closing the opening 103, and the compressed fluid moves past the valve 116 and the opening 107l and then reacts on the left end of the valve stem 58 and urges the same to the right against the biasing effect of the spring 62. As the stem 58 moves to the right,

the passage 66 first moves out of a confluent relationship with the bores 48 and Eiland then the passage 68 moves into a confluent relationship with the bore 48, as shown in FIG. 5, and the pressurized fluid flows through the same and then through conducting tube 26 and into the Pitot opening 20 to blow-out any foreign material therein.

If the pressure in the fluid generated by the first pumping action is not sufficient to blow-out the foreign material, the handle 122 may again be moved to the left to charge the space to the right of the piston 96 with a new supply of fluid. The previous retained charge of pressurized fluid, which is maintained in the valve 36 and conducting tube 26 by the foreign material blocking the Pitot opening, reacts on the right side of the valve 116 and maintains the same closing the opening 107 and also continues to react on the left side of the stern 58 thereby maintaining the stem 5S in its right position, shown in FIG. 5, so that the retained charge of pressurized fluid cannot enter the bore 50 and pass to the indicator 16. Upon again forcing the handle 122 to the right, a further charge of pressurized fluid is forced past the valve 116 and through the passage 63 and bore 4S to react on the foreign material.

When the material is blown-out, the pressure in the conducting tube 26, bore 48, passage 68 and to the left of stem S8 rapidly decreases and the stem 58 is biased to the left by the spring 62. Once the passage 63 moves into bore 52, it becomes blocked and the fluid to the left thereof does not become pressurized to restrict the movement of the stem 53 into abutting engagement with the snap ring 6i) since the valve 116 remains slightly open in its almost closed position, shown in FIG. 1, and the fluid may flow therepast. Since the piston 96 has been forced against the shoulder 106, the fluid flowing past the valve 116 and f through the opening 167 may now urge the piston to the left until it abuts against the spring 104 so that no uid pressure will be built up to the left of stem 58 as it returns to its left position as shown in FIG. 1. When the stem 58 has returned to its left position, the passage 66 is once again confluent with bores '43 and 50 and pressure signals may again pass from the Pitot opening 2t) to the indicator 16.

While only a single embodiment of this invention has been shown and described, it is understood that many changes and modifications can be made therein without departing from the scope of this invention as defined by the following claims.

What is claimed is:

1. A marine speedometer assembly for indicating the speed at which a boat hull is moving relative to the Water supporting the same comprising in combination, a pressure sensitive speed indicating means, means including a Pitot opening means adapted to be immersed in the water and to receive pressure signals generated by the relative movement between said Pitot opening and the water, first conducting means including first and second portions connecting said Pitot opening means to said indicating means for conductin-g pressure signals therebetween with said first portion connected to said indicating means and said second portion connected to said Pitot opening means, and blow-out means confluent with said first conducting means for inducing a reverse pressure to said Pitot opening means, said blow-out means including a manually controllable fluid pressure source means and second conducting means, pressure sensitive valve means operatively disposed in both said conducting means for connecting said source means to said rst conducting means at the junction of said iirst and second portions, said valve means being positioned between said first and second portions and having a first position wherein said iirst and second portions of said conducting means are in a confluent relationship and said second conducting means is blocked from said rst conducting means and a second position wherein said first and second portions are blocked from each other and said second conducting means is joined in a confluent relationship with said second portion while being blocked from said iirst portion whereby fluid pressure will iiow from said source means to said Pitot opening means.

2i. The assembly according to claim 1 wherein said valve means includes resilient means constantly biasing said valve means toward its irst position and said valve means includes pressure sensitive means for moving said valve means to its second position upon the application thereto of uid pressure from said source means.

3. The assembly according to claim 1 wherein said valve means includes a valve stern means having a rst and a second passage means therein and being movable between iirst and second positions, said passage means being so constructed and arranged that when said Valve stem means is in said first position said irst passage means joins said first and second portions in a conuent relationship and when said valve stem means is in said second position said iirst passage means is blocked from said portions and said second passage means joins said second conducting means to said second portion.

4. An assembly according to claim 3 wherein said valve means includes means constantly maintaining said first and second passages in said valve stem blocked from each other.

5. A marine speedometer assembly for indicating the speed at which a boat hull is moving relative to the water supporting the same comprising in combination, a pressure sensitive speed indicating means, means including a Pitot opening means adapted to be immersed in the water and to receive pressure signals Igenerated by the relative movement between said Pitot opening and the water, iirst conducting means including first and second portions connecting said Pitot opening means to said indicating means for conducting pressure signals therebetween with said lirst portion connected to said indicating means and said second portion connected to said Pitot opening means, and blow-out means confluent with said first conducting means for inducing a reverse pressure to said Pitot opening means, said blow-out means including a manually controllable fluid pressure source means and second conducting means, pressure sensitive valve means operatively disposed in both said conducting means for connecting said source means to said rst conducting means at the junction of said iirst and second portions, said valve means including iirst and second bores disposed in a confluent relationship respectively with said iirst and second portions and a third bore confluent with said second conducting means and a valve stem means slidably disposed in at least one of said bores, said valve stem means having iirst and second passageways therein, said valve including means constantly blocking said iirst and second passageways from a continent relationship with each other, said valve stem means having first and second positions and including means for moving the same alternately between said positions and in said first position said first passageway being conuent with said iirst and second portions and said second passageway is blocked from both said portions thereby allowing pressure signals from said Pitot opening to pass to said indicating means and in said second position said iirst passageway is blocked from said rst and second portions and said second passageway is confluent with said second portion whereby uid pressure from said source means may pass therethrough to said Pitot opening.

6. The assembly according to claim 5 wherein said means for moving said valve stem means includes resilient means normally biasing the same to its first position and manually controllable means for moving the same to its second position against the biasing effect of said resilient means.

7. The assembly according to claim 5 wherein said blow-out means includes maintaining means operatively disposed between said source means and said stem means for maintaining residual fluid pressure in said second passageway and said second portion and to said Pitot opening when said Pitot opening is blocked, said maintaining means maintaining said residual pressure and allowing a recharging of said source means with fluid -under pressure and allowing said recharged fluid pressure to ow therepast through said second passageway.

References Cited UNITED STATES PATENTS 1,885,933 11/1932 Masters 73-182 2,105,311 1/1938 Clason 73-182 2,362,298 11/ 1944 Newell 73--182 DAVID SCHONBERG, Prz'mary Examiner. LOUIS R. PRINCE, Examiner.

N. B. SIEGEL, Assistant Examiner. 

5. A MARINE SPEEDOMETER ASSEMBLY FOR INDICATING THE SPEED AT WHICH A BOAT HULL IS MOVING RELATIVE TO THE WATER SUPPORTING THE SAME COMPRISING IN COMBINATION, A PRESURE SENSITIVE SPEED IDICATING MEANS, MEANS INCLUDING A PITOT OPENING MEANS ADAPTED TO BE IMMERSED IN THE WATER AND TO RECEIVE PRESSURE SIGNALS GENERATED BY THE RELATIVE MOVEMENT BETWEEN SAID PITOT OPENING AND THE WATER, FIRST CONDUCTING MEANS INCLUDING FIRST AND SECOND PORTIONS CONNECTING SAID PITOT OPENING MEANS TO SAID INDICATING MEANS FOR CONDUCTING PRESSURE SIGNALS THEREBETWEEN WITH SAID FIRST PORTION CONNECTED TO SAID INDICATING MEANS AND SAID SECOND PORTION CONNECTED TO SAID PITOT OPENING MEANS, AND BLOW-OUT MEANS CONFLUENT WITH SAID FIRST CONDUCTING MEANS FOR INDUCING A REVERSE PRESSURE TO SAID PITOT OPENING MEANS, SAID BLOW-OUT MEANS INCLUDING A MANUALLY CONTROLLABLE FLUID PRESSURE SOURCE MEANS AND SECOND CONDUCTING MEANS, PRESSURE SENSITIVE VALVE MEANS OPERATIVELY DISPOSED IN BOTH SAID CONDUCTING MEANS FOR CONNECTING SAID SOURCE MEANS TO SAID FIRST CONDUCTING MEANS AT THE JUNCTION OF SAID FIRST AND SECOND PORTIONS, SAID VALVE MEANS INCLUDING FIRST AND SECOND BORES DISPOSED IN A CONFLUENT RELATIONSHIP RESPECTIVELY WITH SAID FIRST AND SECOND PORTIONS AND A THIRD BORE CONFLUENT WITH SAID SECOND CONDUCTING MEANS AND VALVE STEM MEANS SLIDABLY DISPOSED IN AT LEAST ONE OF SAID BORES, SAID VALVE STEM MEANS HAVING A FIRST AND SECOND PASSAGEWAYS THEREIN, SAID VALVE INCLUDING MEANS CONSTANTLY BLOCKING SAID FIRST AND SECOND PASSAGEWAYS FROM A CONFLUENT RELATIONSHIP WITH EACH OTHER, SAID VALVE STEM MEANS HAVING FIRST AND SECOND POSITIONS AND INCLUDING MEANS FOR MOVING THE SAME ALTERNATELY BETWEEN SAID POSITIONS AND IN SAID FIRST POSITION SAID FIRST PASSAGEWAY BEING CONFLUENT WITH SAID FIRST AND SECOND PORTIONS AND SAID SECOND PASSAGEWAY IS BLOCKED FROM BOTH SAID PORTIONS THEREBY ALLOWING PRESSURE SIGNALS FROM SAID PITOT OPENING TO PASS TO SAID INDICATING MEANS AND IN SAID SECOND POSITION SAID FIRST PASSAGEWAY IS BLOCKED FROM SAID FIRST AND SECOND PORTIONS AND SAID SECOND PASSAGEWAY IS CONFLUENT WITH SAID SECOND PORTION WHEREBY FLUID PRESSURE FROM SAID SOURCE MEANS MAY PASS THERETHROUGH TO SAID PITOT OPENING. 